LTC6101CIS5TRMPBF View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC6101CIS5TRMPBF Datasheet PDF : 22 Pages
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LTC6101/LTC6101HV
APPLICATIONS INFORMATION
Reverse Supply Protection
Some applications may be tested with reverse-polarity
supplies due to an expectation of this type of fault during
operation. The LTC6101 is not protected internally from
external reversal of supply polarity. To prevent damage that
may occur during this condition, a Schottky diode should
be added in series with V– (Figure 7). This will limit the
reverse current through the LTC6101. Note that this diode
will limit the low voltage performance of the LTC6101 by
effectively reducing the supply voltage to the part by VD.
In addition, if the output of the LTC6101 is wired to a device
that will effectively short it to high voltage (such as through
an ESD protection clamp) during a reverse supply condi-
tion, the LTC6101’s output should be connected through
a resistor or Schottky diode (Figure 8).
Response Time
The LTC6101 is designed to exhibit fast response to inputs
for the purpose of circuit protection or signal transmission.
This response time will be affected by the external circuit
in two ways, delay and speed.
If the output current is very low and an input transient
occurs, there may be an increased delay before the output
voltage begins changing. This can be improved by increas-
ing the minimum output current, either by increasing
RSENSE or decreasing RIN. The effect of increased output
current is illustrated in the step response curves in the
Typical Performance Characteristics section of this data
sheet. Note that the curves are labeled with respect to the
initial output currents.
The speed is also affected by the external circuit. In this
case, if the input changes very quickly, the internal ampli-
fier will slew the gate of the internal output FET (Figure
1) in order to maintain the internal loop. This results in
current flowing through RIN and the internal FET. This
current slew rate will be determined by the amplifier and
FET characteristics as well as the input resistor, RIN. Us-
ing a smaller RIN will allow the output current to increase
more quickly, decreasing the response time at the output.
This will also have the effect of increasing the maximum
output current. Using a larger ROUT will decrease the re-
sponse time, since VOUT = IOUT • ROUT. Reducing RIN and
increasing ROUT will both have the effect of increasing the
voltage gain of the circuit.
RSENSE
R1
+IN
–IN 100
L
V–
O
A
D
LTC6101
D1
V+
VBATT
OUT
R2
4.99k
6101 F07
Figure 7. Schottky Prevents Damage During Supply Reversal
RSENSE
+IN
L
V–
O
A
D
LTC6101
D1
R1
–IN 100
V+
R3
OUT
1k
R2
4.99k
VBATT
ADC
6101 F08
Figure 8. Additional Resistor R3 Protects
Output During Supply Reversal
6101fh
15
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